Field of the Invention
The present disclosure relates to the field of power electronics, and more particularly, to an electronic cigarette and an integrated circuit for the same.
Description of the Related Art
An electronic cigarette is an electronic product which is popular in today's market for replacing a real cigarette. The electronic cigarette typically includes electronic components such as an integrated circuit, a lithium battery, a gas sensor, an atomizer, and the like. The integrated circuit includes power switches and control circuits. The lithium battery needs to be charged, for example, in a charging process controlled by the integrated circuit to supply electric energy from an external adapter to the lithium battery, and store sufficient electric energy before it is used. When the electronic cigarette is used, the lithium battery needs to be discharged, for example, in a discharging process controlled by the integrated circuit to supply electric energy from the lithium battery to the atomizer, so as to simulate smoking by an atomizing process.
FIG. 1 is a schematic diagram of an integrated circuit used in a conventional electronic cigarette. The integrated circuit includes a power switch Q1, a power switch Q2, a charging circuit 101, a boost circuit 102, a driving control unit 103, a capacitor C1, a capacitor C2, and an inductor L1. The charging circuit 101 includes a power switch Q3, a CC_CV (abbreviation of constant current and constant voltage) control circuit 1011. The boost circuit 102 includes a power switch Q4, a power switch Q5, and a PWM control circuit 1021. A connector is used for being electrically coupling to an adapter or an atomizer. When the connectors is electrically coupled to the adapter, the driving control unit 103 detects a voltage of the adapter, turns on the power switch Q2, and the charging circuit 101 operates to charge the lithium battery through the power switch Q3 and the power switch Q2 from the adapter. When the connector is electrically coupled to the atomizer, the boost circuit 102 boosts a battery voltage to a voltage VBOOST, and then the driving control unit 103 controls on and off states of the power switch Q1 to output the voltage VBOOST to the atomizer. The driving control unit 103 detects an average value of the output voltage by a low-pass filter consisting of a resistor R1 and a capacitor C3, compares the average value with an internal voltage reference, and adjusts an on time of the power switch Q1 so that the average value of the output voltage is equal to the internal voltage reference. An output power is thus controlled to be constant.
As shown in the above circuit, the conventional control scheme uses 5 power switches, which results in increased manufacture cost and a complex control process, and will have disadvantages in view of circuit simplification and cost reduction. Moreover, the conventional scheme does not adjust or limit an operating temperature or a current value of the system, and may cause damage of the system when the operating temperature or the current value is too large.